update: found the solution myself. After I additionally installed the MiHome App the Lightstrip immediately got detected and reinstalled propperly. So the problem was the Yeelight App - which btw now is detecting the Lightstrip again, too - after MiHome detected and reinstalled it.

update: found the solution myself. After I additionally installed the MiHome App the Lightstrip immediately got detected and reinstalled propperly. So the problem was the Yeelight App - which btw now is detecting the Lightstrip again, too - after MiHome detected and reinstalled it.